OBJECTIVE: To compare hepatic artery embolization accomplished by Gelfoam, autologus clot, or other commonly used clinical techniques with complete obturation of the heptic arterial bed using an injectible plastic. METHODS EMPLOYED: The proper hepatic artery is selectively catheterized in monkeys and either the right branch or all intrahepatic branches are embolized with 1 to 2 cc of silicone rubber. Serial blood chemical determinants are performed as well as serial x-rays to document the acute insult to the liver. As hepatic function tests return to normal, arteriography is repeated to evaluate the development of hepatic arterial collaterals. The monkeys are sacrificed and their livers studied microscopically. A second group of monkeys undergo embolization of a single hepatic artery branch, usually the right, and will be compared with a group of monkeys whose hepatic arteries are proximally obstructed by Gelfoam, the commonly used clinical technique.